The percent of Americans who are now overweight or obese is at an all-time high. In women of reproductive age, obesity has been associated with depression. Postpartum depression (PPD) affects 10-15% of all women, especially those with a history of pre-existing depression.1 This series of correlations suggests an association between obesity and PPD. Despite this potential association, we are aware of only one study (n=64) that has investigated the potential association between obesity and PPD.2 The central hypothesis of this study is that there is an association between PPD and maternal obesity. More specifically, this association increases as maternal BMI increases and unique risk factors for PPD exist in the obese population. To test this Hypothesis, an interdisciplinary team with expertise in Perinatal Medicine, Psychology, Epidemiology and Mental Health Nursing has designed this translational project in response to PA-03-135 (Women's Mental Health in Pregnancy and the Postpartum Period. Using a prospective design with an oversampling technique, we will: 1. quantify the relationship between body mass index category (BMI) and postpartum depression (PPD) in a sample of women delivering on the obstetric services of two large urban hospitals in Salt Lake City, Utah and 2. identify potential social, psychological, medical, and/or obstetrical risk factors in the obese and non-obese population that are associated with PPD. An added strength of our proposal is it will provide follow-up care and guidance for women diagnosed with psychiatric illness by this investigation. The data derived from this study will be used to develop a prospective intervention trial that is specific to obese women. These interventions could include exercise, nutrition and/or pharmacotherapy, not only to improve physical health of women, but also to decrease the likelihood of PPD and the its consequences in women.